The main reason is the storm surge along low-lying areas in the northen part of the Bay of Bengal. Bangladesh , which is located in the mouth of the Ganges river, is a flat country slightly above the sea level, so once the storm surge occurs, the extensive area will be affected by the storm surge. The huge damage happened several times by the storm surge and flooding, the building of cyclone shelters has been carried out for evacuation.

The infrastructure of this area is fragile, so the huge disaster may occur not only by storm surge but also by heavy rains. As the following shows, the damage in of cyclones is huge not only in Bangladesh but also in India.